The El Nino cycle brings numerous threats to Hawaii — drought, higher risk of hurricanes, and warmer sea surface temperatures that potentially could lead to coral bleaching.

But unlike California, where El Nino’s warmer ocean temperatures are expected to send more great white sharks north to its coastal waters, Hawaii seems to be safe from that potential impact.

Kim Holland, research professor at the Hawaii Institute of Marine Biology and co-founder of its Shark Research Lab, said he strongly doubts Hawaii will see more sharks.

“Compared to the continent and Central and South America, the changes in water temperatures in Hawaii are comparatively small. And equally importantly, Hawaii is in the middle of the normal range of most of the sharks that live here,” he said.

In early June, forecasters from the National Oceanic and Atmospheric Administration officially declared the formation of El Nino, which is triggered when temperatures in the equatorial Pacific are 0.5 degrees Celsius above average.

The El Nino Southern Oscillation, which occurs about every two to seven years, is basically the warm phase of a “seesaw shift” in surface air pressure between the eastern and western portions of the Pacific. NOAA expects El Nino to continue strengthening through the end of the year, and gives it a 97% chance of persisting through the spring.

While every El Nino is different, the usual impacts to Hawaii include weakening tradewinds, increased drought and wildfire risks, and a more-active hurricane season.

With El Nino, sea surface temperatures also have risen above average across the central and eastern Pacific Ocean, potentially triggering coral bleaching events across Hawaii.

Hawaii’s coral reefs are already vulnerable after sustaining damage from the Kona-low storms in March.

Hawaii is home to about 40 species of sharks, including Galapagos, blacktip reef, scalloped hammerhead and tiger sharks, among others, that are already in their comfort zone, even with a slight uptick in temperatures.

Therefore, potential impacts on sharks from El Nino are likely minimal, he said. Whatever changes there will be, will also be too subtle to detect.

“They should be able to adapt,” he said. “It’s typically inside the edges of an animal’s normal distribution or range that changes caused by El Ninos show up. We’re well within the normal habitat of our coastal sharks.”

California is a different story.

Scientists in California are expecting a large influx of juvenile great white sharks to travel north from Baja, seeking cooler waters this year.

A marine heat wave already has brought an early appearance of the juveniles to the shallow waters of Southern California.

Doug McCauley, director of the Benioff Ocean Initiative at the University of California, Santa Barbara, said El Nino is just beginning to strengthen, and is expected to intensify heading into fall and winter.

“We expect to continue to see more white sharks than usual, and that they’ll persist longer into our California winter than they normally do,” he said. “We expect to see them further north than normally.”

In past El Nino years, white shark nurseries have popped up as far north as Monterey, which is usually too cold.

Additionally, there have been reports fish species from more tropical and subtropical habitats, such as mahi mahi, ahi, and ono, in Southern California waters.

McCauley said it’s almost “as if you were to scoop up a piece of Hawaii’s ocean and drop it temporarily off the coast of Southern California.”

El Nino also creates unusual conditions, resulting in oddities such as the appearance of venomous, yellow-bellied sea snakes normally seen in Central America.

It can potentially throw marine ecosystems off- kilter, especially by suppressing the upwelling of cold, nutrient-rich waters from below with zooplankton that kelp forests and fish depend on.

This crash in the bottom of the food chain, in turn, impacts seabirds and sea lions that depend on them.

“We’re bracing for an unusual few months ahead,” he said.

But experts say the increased presence of sharks does not necessarily correlate to an uptick in shark bites or attacks.

The California Department of Fish and Wildlife said data from past El Nino years “shows that an increase in white shark presence has not led to an increase in shark-related incidents, including injuries.”

In Hawaii, likewise, experts say the presence of sharks does not necessarily result in attacks.

The Hawaii Department of Land and Natural Resources has documented two shark incidents so far this year — one off of Cromwell’s Beach on Oahu and one off of Olowalu, Maui.

On May 16, a kayaker encountered a tiger shark about a mile off of Olowalu in clear waters. The shark bit the kayak, and no injuries were reported.

On May 30, a surfer at “Kaiko‘o’s” surf break was attacked by an 8-foot Galapagos shark, suffering major lacerations to his left calf and right foot.

In Hawaii, white sharks are rarely seen, but do occasionally visit.

“This year, so far, is just another pretty typical year,” said Holland. “We have a very low number of attacks and most are not even fatal.”

Any slight uptick, he said, may have more to do with the number of people that are in the ocean for recreation, including farther off shore with stand-up paddleboards and kayaks.

Hawaii nevertheless ranks high on the list of shark attacks, nationally.

In total unprovoked shark attacks, Hawaii ranks second in the U.S., with a total of 162 confirmed by the Florida Museum’s International Shark Attack File, which has tracked them since 1837.

Florida takes the top spot, with 828 attacks, while California takes third place, with 124.

The majority of shark attacks have occurred on Maui due to a wide, shallow, and protected undersea shelf that acts as a natural magnet for tiger sharks, which are at the same time ocean recreation sites for people.

University of Hawaii at Manoa Shark Lab researchers recently identified the first documented mating hub for tiger sharks at Olowalu, Maui, using acoustic tracking data.

Additionally, a new UH study confirmed — after analysis of 30 years of data – that there is a statistically significant spike in shark bite incidents in Hawaii every October.

Researchers said this is likely due to seasonal movements and the fact that October is peak tiger shark pupping time.

Holland said Hawaii likely ranks high in the shark attack file because as a state surrounded by ocean, there are thousands of people in the water daily.

For decades, however, the number of attacks has remained stable, at mostly a handful per year, with no particular pattern.

“The remarkable part is how few attacks there are, when there are so many people in the water every day in Hawaii,” he said.

“We know that we have sharks in the water every day in Hawaii and the fact is, the majority of time, nothing happens.”

He added, “That’s not to say people shouldn’t be careful when they know there’s a shark in the area, but there’s sharks in the area all the time, basically.”

Last year, DLNR confirmed four shark incidents, all of which resulted in lacerations to limbs that range from serious to severe.

In 2024, there were five shark attacks, including one which resulted in the loss of a leg on Maui, and the death of famed waterman and lifeguard Tamayo Perry, who had been surfing at Malaekahana.

Experts recommend swimming, surfing or diving with other people — and not solo — because shark bites most likely result in shock and blood loss that require help.

DLNR also recommends avoiding murky waters, and staying out of the water at dawn, dusk, and night, when some species of sharks may move farther inshore to feed.

Shark incidents in Hawaii

2026

• May 30: Kaiko‘o’s surf break off Cromwell’s Beach, Oahu. A surfer suffered major lacerations to the left calf and right foot after encountering an 8-foot Galapagos shark at 6:30 a.m.

• May 16: A paddler encountered a 12-foot tiger shark about a mile offshore of Olowalu at 3 p.m. The shark bit the kayak.No injuries reported.

2025

• Dec. 9, Kaalualu Bay, Hawaii island. A spearfisher suffered serious lacerations to his leg while trying to disentangle a 6-foot Blacktip reef shark. Considered a provoked incident.

• Nov. 5: Hanalei Bay, Kauai. An off-duty lifeguard surfing about 500 yards from shore suffered severe lacerations to his left leg. Species and length of shark unknown.

• July 18: Makapuu, Oahu. A swimmer suffered puncture wounds and lacerations to the left foot while swimming about 3 feet from shore. Species unknown.

• Jan. 11: Haleiwa, Oahu. A person swimming with sharks suffered severe lacerations to the left arm from a Galapagos shark, length unknown. Considered a provoked incident.

Source: DLNR